Sensitivity of Slack channels to changes in cell volume.

Slack channels were co-expressed with AQP1 in Xenopus laevis oocytes and activated with a voltage protocol, as described in figure 1, under isotonic (A), hypotonic (B) and hypertonic media (C). (D) shows the corresponding I/V curves under isotonic (black), hypotonic (blue) and hypertonic (red) conditions. Control experiments for native, un-injected oocytes (UI, green) and oocytes only expressing AQP1 (violet) are also shown. In (E), maximal currents were measured at the end of the +80 mV depolarizing step under isotonic, hypotonic and hypertonic buffers and the currents were normalized to the current measured at isotonic conditions. Data points in panels (D) and (E) show the mean of 10 independent experiments ± S.E.M. (F) shows a current trace over time for a representative oocyte expressing Slack and AQP1. The channels were activated by a protocol as described in figure 1.